Poden les infeccions autòctones protegir enfront les infeccions exòtiques?

Les espècies, en un hàbitat nou, necessiten trobar un espai lliure on establir-se. Si l'ecosistema té una alta diversitat i tots els nínxols ecològics estan ocupats, l'espècie invasora no tindrà èxit i morirà. Establint una analogia entre els ecosistemes biològics i l'organisme, investigadors de la UAB s'han plantejat si una gran diversitat de simbionts (paràsits i comensals) dins d'un organisme pot dissuadir la infecció per part d'un nou paràsit. Ho han investigat en l'anguila europea, que disposa de paràsits autòctons així com d'un paràsit exòtic, l'Anguillicoloides crassus, introduit degut a una importació massiva d'anguiles asiàtiques infectades als anys 80, i que infecta la vesícula natatòria d'aquest peix.Las especies, en un hábitat nuevo, necesitan encontrar un espacio libre donde establecerse. Si el ecosistema tiene una alta diversidad y todos los nichos ecológicos están ocupados, la especie invasora no tendrá éxito y morirá. Estableciendo una analogía entre los ecosistemas biológicos y el organismo, investigadores de la UAB han planteado si una gran diversidad de simbiontes (parásitos y comensales) dentro de un organismo puede disuadir la infección por parte de un nuevo parásito. Lo han investigado en la anguila europea, que dispone de parásitos autóctonos así como de un parásito exótico, el Anguillicoloides crassus, introducido debido a una importación masiva de anguilas asiáticas infectadas en los años 80, y que infecta la vesícula natatoria de este pez

Estudien quin factor fóra més probable que causés l'extinció dels isards

Investigadors del Servei d'Ecopatologia de Fauna Salvatge (SEFaS) de la UAB han realitzat una aproximació, mitjançant un model estadístic, de les probabilitats que les allaus de neu i diverses malalties infeccioses puguin causar l'extinció dels isards pirinencs. La modelització s'ha fet amb una població hipotètica de 500 isards i considerant el punt d'extinció per sota dels 30 individus. El Border Disease Virus genotip 4 (BDV-4), causant ja d'altes mortalitats en algunes zones dels Pirineus, fóra el que tindria un major impacte sobre la viabilitat de les poblacions d'isards.Investigadores del Servicio de Ecopatología de Fauna Salvaje (SEFaS) de la una aproximación, mediante un modelo estadístico, de las probabilidades de nieve y varias enfermedades infecciosas puedan causar la extinción de los reb modelización se ha realizado con una población hipotética de 500 rebecos y co de extinción por debajo de los 30 individuos. El Border Disease Virus genotipo causado ya altas mortalidades en algunas zonas de los Pirineos, sería el qu impacto sobre la viabilidad de las poblaciones de rebeco

Es descobreix un patró d'ossificació comú en els ungulats

Tots els vertebrats tenim un esquelet ossi. Però la formació dels ossos varia entre individus i entre espècies. Investigadors de la UAB han trobat un patró d'ossificació en els Ungulats, nom genèric de qualsevol mamífer les extremitats del qual acaben en peülles, diferent en funció de si els ossos estan sotmesos a tensions o a pressions. Aquesta nova aproximació pot ser aplicada a l'estudi de fòssils de mamífers extints i ser útil tant per establir relacions filogenètiques de parentiu com per conèixer aspectes funcionals de l'evolució dels vertebrats.Todos los vertebrados tenemos un esqueleto óseo. Pero la formación de los huesos varía entre individuos y entre especies. Investigadores de la UAB han encontrado un patrón de osificación en los Ungulados, nombre genérico de cualquier mamífero cuyas extremidades terminan en pezuñas, diferente en función de si los huesos están sometidos a tensiones o presiones. Esta nueva aproximación puede ser aplicada al estudio de fósiles de mamíferos extintos y ser útil tanto para establecer relaciones filogenéticas de parentesco como para conocer aspectos funcionales de la evolución de los vertebrados

Efectes recíprocs entre la ramaderia bovina en extensiu amb finalitats ambientals i la vegetació mediterrània

La biodiversitat està en el punt de mira de les polítiques agroambientals davant l'amenaça d'incendis i l'arbustització que la deterioren. Per tal de preserva-la i controlar aquests dos fenòmens, es va provar l'opció de la ramaderia extensiva i es va exposar bestiar boví a la vegetació llenyosa mediterrània com a única font de menjar. Si bé es va percebre un canvi de preferències alimentàries, cosa que solucionaria el problema, l'anàlisi d'aquesta dieta va indicar que malmetia la salut dels animals.La biodiversidad está en el punto de mira de las políticas agroambientales ante la amenaza de incendios y la proliferación de arbustos que la deterioran. Para su conservación y control de estos dos fenómenos, se probó la opción de la ganadería extensiva y se expuso ganado vacuno a la vegetación leñosa mediterránea como única fuente de comida. Si bien se percibió un cambio de preferencias alimentarias, lo que solucionaría el problema, el análisis de esta dieta indicó que dañaba la salud de los animales

Feeding Preferences of Domestic and Wild Ungulates for Forage Trees in the Dry Tropics

Silvopastoralism based on livestock feeding on forage trees is becoming a sustainable alternative to traditional grazing on the open pastures of dry tropical Central America. Four autochthonous trees, Acacia pennatula, Enterolobium cyclocarpum, Gliricidia sepium and Guazuma ulmifolia, and one exotic (Moringa oleifera) tree are the preferred species for these silvopastoral systems. Little is known, however, about the feeding preferences of cattle, sheep and goats for such fodder trees and whether wild ungulates (white-tailed deer, Odocoileus virginianus) feed on these plants. In this work, we conducted several multiple-choice feeding preference tests (cafeteria test) to compare the best choice to feed cattle, sheep, goats and white-tailed deer in these farming systems. Although all ruminant species included the four autochthonous trees and the exotic M. oleifera in their diets, G. ulmifolia was the preferred forage tree by far. The preference for the rest of the trees varied among our ruminant species. When M. oleifera was added to the cafeteria test, it was well accepted by white-tailed deer but little appreciated by their domestic counterparts. The use of these forage trees for livestock feeding is thus interesting not only for sustainable animal production but also to support wild herbivores in the dry tropics of Central America

Equal contributions of feline immunodeficiency virus and coinfections to morbidity in African lions

Feline immunodeficiency virus (FIV) is a pathogenic lentivirus related to human and simian immunodeficiency viruses that has been associated with AIDS-like pathologies in domestic and wild cats, as well as in hyenas. Despite known pathologies, progressive immunosuppression and ill health effects driven by these lentiviruses in association with other secondary infections remain understudied in free-ranging species. Here, the role of coinfections by gastrointestinal parasites and tick-borne hemoparasites for FIV disease progression was explored in 195 free-ranging African lions (Panthera leo) living in Kruger National Park (KNP), South Africa. Using statistical methodology, we evaluated the effects of FIV on a range of health indicators to explore how direct and indirect effects of FIV and associated coinfections align to determine lion health outcomes. Findings show direct negative effects of FIV on host immunity and nutritional status, and exacerbation of aggressive behaviors, conditions which may increase exposure/susceptibility to other secondary infections. When taken together, the contribution of coinfecting parasites to morbidity in lions is of similar magnitude as direct effects of FIV infection alone, suggesting that the particular coinfection assemblage may play a role in mediating disease progression within natural lion populations

Parasite intensity drives fetal development and sex allocation in a wild ungulate

Altres ajuts: Natural Sciences and Engineering Research Council of Canada 316189-2012-RGPIN. Beringian Coevolution Project (BCP), National Science Foundation DEB 0196095 i 0415668An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall's sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. Principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change

The synzootic potential of common epidemics in chamois populations

Altres ajuts: acords transformatius de la UABSouthern chamois (Rupicapra pyrenaica) is a medium-sized and gregarious mountain ungulate with populations affected by periodic outbreaks of border disease virus (BD), infectious keratoconjunctivitis (IKC), and sarcoptic mange (SM). Even though the impact of each disease on chamois populations has been described in detail, there is a lack of information about the potential impact of concomitant epidemics and the synzootic potential (co-occurring enzootic or epizootic processes producing worse health outcomes in wildlife) on chamois populations. Furthermore, whether a specific order of apparition of epidemics is more or less harmful for the host population is practically unknown not only for chamois but also for most mammal populations. Using a population viability analysis (PVA), we studied the consequences of multiple disease outbreaks with synzootic potential on growth rates and probabilities of extinction of virtual populations exposed to hard winters, density dependence, and co-occurring BD, IKC, and SM outbreaks. Such infections are not under cross-immunity nor density-dependent processes and thus are supposed to affect population demography independently. Heavy snowfalls are also likely to occur in our simulated populations. Our simulations showed that a second outbreak, even caused by a low virulent pathogen, causes an increase in the probability of extinction of the host population with regard to the first outbreak. IKC-BD- and SM-BD-affected populations had a higher risk of becoming extinct in 50 years confirming the extra risk of multiple outbreaks on the viability of the affected populations

Comparing the accuracy of PCR-capillary electrophoresis and cuticle microhistological analysis for assessing diet composition in ungulates : a case study with Pyrenean chamois

The study of diet composition is required to understand the interactions between animal and plant ecosystems. Different non-invasive techniques applied on faecal samples have commonly been used for such purposes, with cuticle microhistological analysis (CMA) and emerging DNA-based methods being the most relevant. In this work, we refined and optimized a qualitative DNA-based approach combining PCR amplification of long trnL(UAA) and ITS2 fragments and capillary electrophoresis (PCR-CE), instead of short trnL(UAA) fragments and massive sequencing technologies commonly reported. To do so, we develope a controlled diet assay using a stabled Pyrenean chamois specimen (Rupicapra pirenaica pyrenaica), which included representative herbaceous and shrubby plant species. We also assessed the impact of sample freshness on the diet determination of this mountain caprinae by exposing faecal samples to the outdoor environment for three weeks. Faecal samples from both experiments were analysed by qualitative PCR-CE and semi-quantitative CMA in order to compare the pros and cons of both approaches. Our results show that all of the offered plant species were detected by both methodologies although CMA overdetected shrubs compared to herbaceous species. At the same time, sample degradation due to sustained climate exposure is a limiting factor for molecular analysis, but not for CMA. Taken all together, our results suggest that the qualitative information obtained by CMA and PCR-CE can be interchangeable when faecal samples are fresh (less than one week after deposition) but, afterwards, molecular analysis underestimates diet composition probably due to DNA degradation. CMA, however, can accurately be used at least three weeks after defecation. Moreover, by combining the results of simultaneous PCR amplification of two complementary genes, this optimized PCR-CE methodology provides a reliable, feasible and more affordable alternative for multiple and routine analyses of complex samples. Neither CMA nor PCR-CE seems to solve comprehensively the quatification of herbivore diets and thus further research needs to be done